Radiator core



Nav. 30, 1943. A. B. MoDlNE RADIATOR GORE Filed Aug. 25. A194,1

2 Sheets-Sheet 1 Nqv. 30, 1943. A. B. MoDlNE 2,335,687

RADIATOR CORE l Filed Aug. 25. 1941 2 sheets-sheet 2 Patented Nv. 30, 1943 RADIATOR CORE Arthur B. Medine, St. Petersburg, Fla. Application August 25, 1941, Serial No. 408,186 4 Claims. (CL 13S-38) The invention relates generally to heat transfer cores, and more particularly to a novel construction of the so-called cartridge type of core.

The invention has among its objects the production of such a core in which the elciency of the core is increased with a savingv in cost, materials, and weight.

Another object of the invention isthe producwhich is secured upper and lower headers 2 and4 3, respectively. The core I comprises a. plurality of relatively short lengths of tubing 4 stacked in parallel relation and secured together adjacent their corresponding ends. As clearly shown in Figs. 2, 4 and 5, each tube is upset or otherwise formed at its respective ends with an enlarged portion 5, the portions in the present instance tion of va core of the type described irl-whichfewer tubes are required to construct a core ofcomparative size and efiiciency with the-'present cores, and at the same time decreasing the hfo'r'se power drag of the core by lessening the ailjlresistance through the novel iin arrangement ofthe COTE.

A further object of the invention is thefconl struction of such a core embodying a novel n" construction for increasing the heat exchange capacity of the core, which fins are constructed` L.

to facilitate and simplify the assembling of the cores. v

The invention particularly adapts itself in the aviation industry, wherein it is necessary to have .maximum efficiency and minimum weight and air resistance.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end, my invention consists in the novel construction, arrangement and 'combination of parts herein shown and described, and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts:

Fig. 1 is a front elevational view of a heat transfer core or radiator embodying the present invention;

Fig. 2 is anl enlarged view of a portion of the structure illustrated in Fig. 1;

Fig. 3 is a vertical sectional View through a portion of the core;

Fig. 4 is a sectional view taken approximately on the line 4-4 of Fig. 2;

Fig. 5 is a perspective view of one of the tubes and iin elements with a portion of the same shown in section;

Fig. 6 is a perspective View of a portion of a tube and modified form of iin element;

Fig. '7 is a view similar to Fig. 6 illustrating another modiiied form of flnv element; and

Fig. 8 is a view similar to Fig. 6 illustrating still another form of fin element.

The device illustrated in Fig. 1 comprises a core designated generally by the numeral I to and 9 may be employed at the top and sides of the -core to even the respective edges of the core, side being hexagonal in cross section, as clearly illustrated in Figs. 2 and 3. These tubes are co-extensive in length and are stacked in parallel relation with adjacent sides of the enlarged portions 5 in engagement with one another and bonded together to form an integral structure. Due

to the-enlargement of the end portions 5, channels 6 between the intermediate portions I of the tubes are formed, the channels 6 being sealed from the ends of the tubes by the enlarged portions 5.

Any suitable means such as. for example, tubes 8 plates II illustrating one manner of sealing the side of the core. Likewise, any suitable header construction may be employed, the upper header in the drawings being provided with a plurality of flanges I2 secured to the top of the core and flanges I3 on the side members II. It will be apparent that the channels 6 between the intermediate portions 'l of the tubes provide means for the passage of uid from the upper header 2 to the lower header '3, the channels being sealed adjacent the ends of the tubes and at the sides of the core. It will be also apparent that the passages I4 through the respective tubes provide means for the flow of air or other fluid through the core, whereby transfer of heat between the uid passing through the channels 6 and the fluid passing through the passages I4 may be obtained.

In the past, cartridge type cores such as that just described have been constructed from tubing of approximately .230 inch outside diameter, with the channel between the tubes approximately .03 inch, necessitating approximately 2460 tubes per square foot of frontal area of the iinished core. It was impractical to use larger diameter tubing as the latter required larger channels between the heat transfer capacity of the core would be reduced, as obviously with the larger tubes a smaller number of tubes would be employed and the area of the heat conducting surface diminished. With the present construction larger tubes can be employed. 'I'he outer diameters of the tubes in the present instance, for example, could be .375 inch and the channel .045.

The tubes 4 are each provided with a fin element I5, these elements in the construction illustrated in Figs. 2, 3, 4 and 5 being formed from a flat strip of material which is bent back upon itself to form an element of substantially U-shape in cross section. The metal from which the elements I5 are constructed is preferably flexible, so that the side walls I6 thereof tend to diverge, while the width of the side Walls is such that the longitudinal edges of the side walls and the portion Il connecting the side walls I6 will engage the inner surface of the respective tube in which it is inserted. To facilitate the insertion of the iin in the tube, the free longitudinal edges of the walls I6 may be flexed toward one another, after which the fin may be readily inserted in the tube. Upon release of the flexed side walls, the free edges thereof will move outwardly, engaging the inner surface of the tubing, and the normal resiliency or flexibility of the iin element Will securely retain the same in proper position in the tube until they are bonded to one another.

The core is constructed and assembled in the following manner: The tubing is cut to the required length and upset or otherwise formed at the respective ends to form the enlarged portions 5. The formed fin elements coated with a suitable bonding material, are then flexed and inserted in the respective tubes. The ends of the tubes, either before or after this operation, may also be provided with a coating of suitable bonding material at the enlarged portions 5. The tubes may then be stacked in parallel relation as illustrated in Figs. 2, 3 and 4 and subjected' to heat in a hydrogen furnace or other suitable device to bond the tubes and iin elements to one another, thereby forming an integral structure. It will be apparent that the core could be bonded together in other Ways, as for example, by dipping the front and rear faces of the assembled core into molten bonding metal and thereby securing the tubes to one another, bonding the iin elements to the tubes either before or after such operation, this depending in large part on the particular bonding metals employed and their various melting points.

'I'he fin elements I5 divide the respective tubes into three passageways of approximately the same area, and as the side walls I6 are secured at both longitudinal edges thereof and at the connecting portion Il to the tube wall, a very elcient heat transfer core results. With the present construction as compared with prior constructions, using for comparison the dimensions heretofore referred to, it will be apparent that denite advantages result from the use of the present construction. Based on equal cooling, the saving on cost of material is over a third, with approximately 18% saving in core weight and approximately 181/2% saving in horse power drag. Similarly, based on like frontal areas, almost as great a saving in cost would result, with a saving in weight of approximately 11.6% and an approximate saving of 26.2% in horse power drag. Y

It will be apparent from the above that this core, having these desirable characteristics, affords a long sought need in applications where maximum cooling capacity with a minimum of I5, after beingA weight and horse power drag are desired, such as in the aviation industry where weightA and air resistance are important factors.

Theiin elements may be formed in various shapes other than the U-shape illustrated in Figs. 2, 3, etc., although I have found the U-shaped member very eiiicient for the purposes intended and easily formed and assembled with the tubes.

In the construction illustrated in Fig. 6 two i111 elements I8 and I9 are employed, the latter being of substantially Vshape in cross section. The element I9 is provided with a longitudinally extending groove or channel 2| positioned at the apex or corner of the element, the channel being of a size to receive the apex or corner of the member I8, so that when the elements are inserted in the tubing they will be securely held in position. As in the case of the U-shaped iin element, the elements I8 and I9 are preferably of such transverse dimensions to require flexing of the elements when inserting the same in the tube, whereby the elements will be held in the tube during assembling of the core.

Illustrated in Fig. 7 is a substantially triangular shaped iin element 22, the assembly of which in the tubing is similar to that described for the U shaped element.

Illustrated in Fig. 8 is a fiat thin element 23 Which is positioned in the tubing to divide it into two passages more or less equal in area. This iin element likewise may have a lateral width slightly greater than the diameter of the tubing, whereby upon flexing the iin element and inserting it in the tubing, it will engage the inner surface of the tubing to maintain the iin element in position until bonded thereto.

It will be apparent from the above description that I have provided a novel heat transfer core construction, as well as novel means for retaining the fin elements in the respective tubes until the same may be bonded together to form an integral core. It will also be noted that I have provided a heat transfer core having improved heat transfer characteristics, with a saving in cost, materials, weight and horse power drag.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence I do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described, or uses mentioned.

What I claim as new and desire to secure by Letters Patent is:

1. A fin for a tube of a heat transfer core comprising an expandible element having three point contact against the inner wall of said tube, two of said contact points of said element comprising terminal portions of the element presenting sharp edges adapted for biting contact with the tube wall to counteract rotation of said element within said tube, said terminal portions being movable relative to each other and relative to the third contact point of said element whereby the complete element can be inserted into said tube and then frictionally held in a predetermined position for bonding to said tube wall.

2. A iin for a tube of a heat transfer core comprising an expandible U-shaped element having three point contact against the interior of said tube, two of said contact points of said element comprising the terminal extremities of the legs of the-U-shaped element each having sharp edges for engaging the inner tube wall thereby together preventing rotation of said element within said tube, said terminal extremities of the legs being movable relative to said third contact point and relative to each other, whereby said element can be freely inserted endwise into said tube and subsequently held in a predetermined position therein for bonding to said'tube wall.

3. A iin for a smooth round tube of a heat transfer unit comprising a ilexible element having leg portions and a connecting portion for joining the same, said connecting portion beingA adapted to abut the inner wall of said tube at one point, and said leg portions each terminating in short cornered edges, the legportions being adapted to spread with sharp cornered edges thereof contacting the inner wall oi said tube at spaced points to maintain said connecting portion in contact with the tube wall at said one point and t'o frictionally hold the entire element in a fixed position and against rotation or endwise displacement within said tube.

4. A iin for a tube oi!y circular cross-section for a heat transfer unit comprising an expandible element of less over-al1 height than the internal diameter of said tube, said element having one lineal portion thereof in contact with the inner wall of the tube at a point on one diameter of said tube, and said element having two other lineal portions thereof disposed for contact against the inner wall of said tube at spaced points oppositely disposed to the aforesaid one diameter and remote from the point of contact of said one lineal portion with said tube, each of said two other lineal portions of said element terminating in a straight sharp edge with a corner of the edge of one portion engaging said inner wall of the tube to counteract rotation of the element in one direction, while a corner of the edge of the other portion of the element engages said inner tube wall to counteract rotation of the element in the opposite direction.

ARTHUR B. MODINE. 

